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View Full Version : Water Changes: What's the point?


Rack Ops
12/31/2008, 04:19 PM
As I browse the forums, the need to change water (at least periodically) seems to be one thing everyone agrees on....how much needs to be swapped out remains a point of debate.

Don't take the title of my post to mean that someone with no experience (me) knows better than you guys...because I'm well aware that I don't.

Anyways, the point of water changes is to get "bad things" out (nitrates, ect) while putting "good things" (trace elements) in.

As I understand it, the bad things can be removed naturally using live rock, a cleaning crew, mangroves, ect.....adding trace elements seems even more straight-forward, just put 'em in w/ a solution.

calli
12/31/2008, 04:22 PM
As I don't know everything but...

I have heard that if you do it once a week about 10% and if once a month 30%.. but I don't know for sure...
I think you kinda have to go with the flow and your test numbers will tell you...

but again I would also like to know a for sure number on this...

ReiferMadness
12/31/2008, 04:30 PM
In the past I changed out 10% per week without fail. I look at it this way, in the ocean there is water constantly moving but in my tank there's not.

I know there's a science to it and the big dogs on RC will explain more but I look at it like any other service that I have with my pets. I give them clean water to refresh their environment.

With my new 50g that's currently cooking I haven't made any water changes but once inhabitants come into the picture I will change it every Saturday.

jenglish
12/31/2008, 04:44 PM
<a href=showthread.php?s=&postid=14051672#post14051672 target=_blank>Originally posted</a> by Rack Ops
As I browse the forums, the need to change water (at least periodically) seems to be one thing everyone agrees on....how much needs to be swapped out remains a point of debate.

Don't take the title of my post to mean that someone with no experience (me) knows better than you guys...because I'm well aware that I don't.

Anyways, the point of water changes is to get "bad things" out (nitrates, ect) while putting "good things" (trace elements) in.

As I understand it, the bad things can be removed naturally using live rock, a cleaning crew, mangroves, ect.....adding trace elements seems even more straight-forward, just put 'em in w/ a solution.

A cleaning crew does not remove nutrients, merely breaks them down or binds them up in biomass. I'm not saying CUC is not important but they still poo the things they eat.

The only way live rock or sand remove nutreints is in anaerobic zones where it is broken down into nitrogen gas to be dissipated. Most of what happens is breaking it down to nitrate or binding up of phosphate.

mangroves, macro fuges, and micro algae based removal require the harvesting of biomass to truley remove it from the system.

Dosing of trace elements can be used to replace them. But by the time you test and dose chemicals and do maintenance on most nutrient removal systems it has become more of a PITA than just changing the water.

There are also those who use anaerobic denitrification systems and phosphate reactors to remove nutrients and reduce or elimnate wc. These also involve some cost and maintenance schedule.

THere are many ways to keep an aquarium, and I am not here to say any one is better than the other. Most people I have known that keep aquariums for years that try any of the little or no WC methods ultimately go back to at least monthly WC. No matter what method you go for it ends up taking time and money to do. But if it didn't i would lose interest ;)

greenbean36191
12/31/2008, 05:47 PM
You make the assumption that all "bad things" can be easily removed in other ways and that you can easily test for and add all of the "good things." Neither is the case.

jbird69
12/31/2008, 05:49 PM
Thereve been a few reported success stories w few to no water changes. Give it a try and see what happens. If things start to look bad, do water changes.

Jay

JBuffetReefer
12/31/2008, 06:33 PM
I think the amount and frequency of WCs depends on a few factors like the size of your tank, # of fish and how much you feed them along with the type of filtration you have. Low bio load and large tank with good filtration will require less WCs.

texhorns98
12/31/2008, 06:36 PM
A friend of mine hasn't done a water change in well over a year! His parameters are all good and stable (save his 15 ppm nitrates), and his tank seems pretty darn healthy. I'm not saying do it (I change 15% every other week), but people have pulled it off somehow.

Gary Majchrzak
12/31/2008, 06:44 PM
<a href=showthread.php?s=&postid=14052534#post14052534 target=_blank>Originally posted</a> by texhorns98
A friend of mine hasn't done a water change in well over a year! His parameters are all good and stable (save his 15 ppm nitrates), and his tank seems pretty darn healthy. I'm not saying do it (I change 15% every other week), but people have pulled it off somehow.
I'm sure we all know of somebody like this yet IME the best reef aquariums (by far!) are the ones that receive (at least!) regular partial water changes. This is all a matter of opinion, though :)

isgon26
12/31/2008, 07:22 PM
I do 20 percent every 3-4 weeks. My setup has not problem. All i run is a protein skimmer and uv light as filtration. Also have a refugium with cheato in it and 7 inch sand bed to kill nitrates.

fishox
12/31/2008, 07:46 PM
Over the past couple summers I have been heavily involved with youth baseball. There is about a 3 month period where I am basically cutting grass by flashlight. Needless to say, my aquarium maintenance suffers too. I have gone 4 months w/o a water change with no appreciable change in my water parameters. My NO3 got to 5 this summer. I think water change intervals are more a function of bio load, inhabitants and equipment than time. While I am not trying to say that frequent partial changes aren't good I don't think they are always necessary. My tank is lightly stocked, I have a good skimmer, I do daily maintenance, and I have a ton of live rock so it seems I can get away with an extended time between changes. Your mileage may vary.

dbrann11
12/31/2008, 08:07 PM
I tend to use water changes to avoid dosing calc and such (which i realize is in vain for the most part), or to get an out of control parameter in control (nitrates/phosphates. There is a thread around here about a 40g skimmerless system that has had 1 waterchange since july or something like that, it's gorgeous.

IMHO if you have a bunch of fish and feed them often you're going to need to do frequent water changes.

noboddi
12/31/2008, 08:20 PM
I do about 20% weekly.

My rule of thumb is if I can't test for it I don't add it to my system. With water changes I get the elements added back in in the right ratios. Never have to worry about adding too much of anything.